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Anodizing Titanium

Hi guys,
I don't offer any of my stuff anodized but I have had a number of questions through the years about anodizing titanium and I have been meaning to take a quick video demonstrating how one might color their light or other titanium part. I just built a Ti UV light for myself because I let one of you talk me out of my UV PD. I wanted to make this light obviously different than the many white LED lights that are always laying around and I have used anodizing on some other lights to identify them as something other than "white".

In the video, I also anodized a Ti-20 clip. The items seen in the video are these:

This thread can go anywhere you guys want it to including down into the dregs of ignored CPF threads.

I would add that I think the clear oxide film of titanium along with the other refractive metals is fascinating in itself and how you perceive color by virtue of light waves interfering with each other and not due to the absorption of some of the spectrum and reflection of the balance.

I consider anodized titanium for the most part to be a cosmetic feature and unless the anodized surface is reasonably protected or recessed, the film can and will abrade over time and show this wear. On the other hand, there are some situations where having the option of coloring a part does give you means of identification, beyond cosmetics.

In the video, I touched on the point that when you anodize titanium, you don't want any other metal in the bath and part of the electric circuit. If there is another metal. It typically just bubbles away in the bath in that area and you don't get a good film growth on the Ti surface itself. I have used this feature in the past to confirm the claims of some items I bought which were stated to be "all" titanium. In many cases, the claims were false. It's probably silly but for me, there is a certain pride in purity in the fact that I can take one of my titanium lights, as is and even turned on, and throw it in an anodize bath and have it change color uniformly in all exposed surfaces. If you take the light apart, you can see where the seals sealed and there is no anodize color beyond.

Re: Anodizing Titanium

Re: Anodizing Titanium

Originally Posted by Drywolf

That was easy! I'll have to try it myself.

I should point out that you don't want anything but Ti anywhere in the bath and that includes your anode and cathode leads to the part being colored. In my demonstration, I have a platinumized titanium cathode rack inserted in the beaker but a strip of titanium will work as well. The clamp and tweezers I used are both titanium.

I got the recipie for the ammonium sulfate some where, probably close to 20 years ago and found some at the local chemical supply house. I guess it is a common fertilizer and available from nurseries as well perhaps. There are other solutions that will work as well and I have heard of some folks using Coke. It worked in a simple test I once did on a reported to be titanium rudder shaft as I mentioned on the video.

Re: Anodizing Titanium

WOW !
I thought it would take much longer and some really elaborated techie stuff, like Dr. Zarkov's lab or something like that.

Thanx for sharing !

bernie

P.S.: I gave my wife a pink anodized ti light (La Petite Killer) and it lost its finish in a few weeks on the keychain almost completely except in the recessed areas. Beautiful, too, but not what I intended.

There is a type of perfection that transcends the quest for lumens. Buying a $250 1-cell light for "lum factor" is like buying a $250 single malt Scotch for the alcohol content. - paulr
It's always darkest just before it goes pitch black.
My shoes are too tight. But it doesn't matter, because I have forgotten how to dance.

Re: Anodizing Titanium

Originally Posted by Kiessling

WOW !
....I gave my wife a pink anodized ti light (La Petite Killer) and it lost its finish in a few weeks on the keychain almost completely except in the recessed areas. Beautiful, too, but not what I intended.

Yeah,
The oxide film is reasonably hard but it is really thin!! I think the best applications, cosmetic wise, are when the colored surfaces are below the typical contact surfaces. I have some wind chimes that I anodized many years ago and they still look like they did on day one but then they are not subject to any real contact beyond the elements which can't effect the surface (sand and hail storms not included).

It is fun to play with because you basically get instant color. If you zap a part at say 40 volts and get a green/ gold color, that color will hold provided you don't subject the part to higher voltage. You could then unmask or cut through the anodize and hit the part at a lower voltage and get a new color anywhere the 40 volt oxide layer was not present. Variations in the surface texture will look different from each other even if anodized at the same voltage. The transition from bead blasted to polished, for instance.

Maybe some of the chemists can chime in here on what is actually happening as the oxide layer is formed.

If you can do your own anodizing then you are in a position to touch up any of your stuff in a jiffy.

Re: Anodizing Titanium

So, how well would that work using the Coke-a-Cola and a 12v. DC source? Do you really just pour some Coke in a glass beaker and hit it with an anode and cathode at 12volts?

I'll let you guys figure out if Coke-a Cola is a viable anodize bath. I don't drink soft drinks so I don't have any to experiment with. I believe you will find with 12 V you will get a gold or bronze color in the Ti. I remember trying to find an old model train transformer when I got the bug to experiment with anodizing the Ti but I ended up with the local electronics house guys aiding me in building my own variable power supply.

One advantage to the anodizing with electricity over the heat coloring of Ti is the control and repeatability you have. I saw some sample chips at a big custom model shop a number of years back that looked like paint sample cards but they were Ti squares in a rainbow of colors you could order. This shop did the big sun for the new (at the time) Disney Adventure Park in So. Cal. The sun is titanium or at least I was told that this company was making the sun for Disney out of titanium. (zero maintenance and no need to refinish or paint!!)

It was interesting because this guy I was talking to (business call for the company I was working for at the time) was a pretty sharp and interesting fellow and in talking to him he mentioned that titanium could not be polished to a high mirror finish. I said I guess it's relative and I went to my van and grabbed my shaving kit that I had fabricated out of Ti and some of the surfaces were mirror enough for me:

He was surprised and admitted that he had no personal experience with trying to polish the metal but took it on the word of someone else. I would imagine that it would not be cost effective to polish up sheets of Ti for architectural applications but we've seen some of the work some CPFer's have done in polishing their Ti lights!!

Re: Anodizing Titanium

I can imagine anodised pistons in my lights ...

The Sun made of anodised ti is really amazing.

There is a type of perfection that transcends the quest for lumens. Buying a $250 1-cell light for "lum factor" is like buying a $250 single malt Scotch for the alcohol content. - paulr
It's always darkest just before it goes pitch black.
My shoes are too tight. But it doesn't matter, because I have forgotten how to dance.

Re: Anodizing Titanium

That is awesome!
Thats for the vid Don.
I have a few annoed Ti lights, well one anno and one coated. The coated one is a AlTiN PD-S, probably my favorite light, (besides the fact that it is a PD-S!) because the coating is durable, gives a nice grip with its rubbery feel, and it has a nice stealthy look that varies between black and purple depending on the surrounding light. The other is a blue anno Ti Nautilus that is just stunning.
I find the colors that can be achieved through different techniques (acid bath or heat, or coatings) facinating, and some of the work done by our members here is just beautiful (my favorites would be from Peter Atwood), and it just adds to the verstility of this uber-cool metal.

Here is a shot of my blue Nautilus with a naked Ti and a annoed aluminum.
Though they are not all Ti with that brass peaking through!

Re: Anodizing Titanium

Re: Anodizing Titanium

Originally Posted by luxlunatic

That is awesome!
Thats for the vid Don.
I have a few annoed Ti lights, well one anno and one coated. The coated one is a AlTiN PD-S, probably my favorite light, (besides the fact that it is a PD-S!) because the coating is durable, gives a nice grip with its rubbery feel, and it has a nice stealthy look that varies between black and purple depending on the surrounding light. The other is a blue anno Ti Nautilus that is just stunning.
I find the colors that can be achieved through different techniques (acid bath or heat, or coatings) facinating, and some of the work done by our members here is just beautiful (my favorites would be from Peter Atwood), and it just adds to the verstility of this uber-cool metal.

Here is a shot of my blue Nautilus with a naked Ti and a annoed aluminum.
Though they are not all Ti with that brass peaking through!

That blue Nautilus was ano'd by Peter Atwood. If you ever want to trade it, please let me know.

Re: Anodizing Titanium

Originally Posted by Sgt. LED

What voltage is orange! Also does leaving it in longer grow a thicker layer?

There are a number of colors that you can't seem to get. I don't recall ever seeing orange, for instance. My rig doesn't allow me to get the range that I have seen possible. For the best results, you want really clean and "fresh" titanium and I have messed in the past with "No-San" which is (was?) a substitute for hydrofluoric acid (really nasty stuff by all accounts) which etched the oxide film off the Ti leaving it relatively virgin. Even the No-San was a bit spooky as I noticed I couldn't store it in a pyrex beaker because it would eat away at the glass and loose its potency.

Provided you have enough power, in a very short time, the film will grow to its final thickness (based on voltage) and extended exposure has no effect on the thickness or resulting color. If you say mask the part and start with a high voltage, you can expose bare metal then, at a lower voltage and not have the first color (higher voltage) change at all. Unlike iron oxide (rust) that can continue to grow into the metal, the titanium oxide film is relatively stable and protects the underlying metal from any change.

Re: Anodizing Titanium

I get color that is near to orange at 65-75 VDC in a bath of baking soda and water. I prepare the titanium target with a soapy wash, alcohol bath, water rinse, short lye soak and a final water rinse.

Here is a pic: From left to right, the first two missed the lye (drain cleaner solution) bath, the last three got the full treatment. Voltages:
75, 70, 75, 70 and 65 VDC.

The best orange is the second to the last, lye bath & 70 VDC in a solution of well water and baking soda.

Notice how the first two, left to right, are pinkish, in spite of the fact that they got the same voltage in the baking soda bath. Those two, however, did not get the lye prepatory bath. So depending on the preparation your mileage may vary.

Re: Anodizing Titanium

Re: Anodizing Titanium

I wish I had a capable USB microscope so that I could get a real close look at the titanium surface before and after lye or acid immersion and share what I see online. I want to see what is going on at the micro level.

Perhaps one of you has such a rig.

Intel used to make a toy one that was priced affordably. I used an early version to do a series of edge comparisons when a micro bevel was added to the cutting edge. It was informative but I don't have access to that usb microscope any longer.